"Our study shows that oxytocin not only plays a role in modulating cooperation and benevolence, but also in driving aggression," said researcher Carsten De Dreu of the University of Amsterdam.

Prior research has shown that oxytocin, also known as the "love hormone," contributes to protectionist behavior, especially in mammalian mothers. De Dreu and colleagues wanted to explore whether the hormone might also play a role in making men more aggressive toward outsiders. De Dreu calls the pairing of in-group solidarity and out-group aggression "parochial altruism," or the "tend and defend" response.

If I love you more, I will be more likely to hate anyone who hurts you. Makes sense.

Still, it's unlikely that the military will have soldiers whiffing oxytocin any time soon. I think amphetamines are working just fine for them.

"Our study shows that oxytocin not only plays a role in modulating cooperation and benevolence, but also in driving aggression," said researcher Carsten De Dreu of the University of Amsterdam.

Prior research has shown that oxytocin, also known as the "love hormone," contributes to protectionist behavior, especially in mammalian mothers. De Dreu and colleagues wanted to explore whether the hormone might also play a role in making men more aggressive toward outsiders. De Dreu calls the pairing of in-group solidarity and out-group aggression "parochial altruism," or the "tend and defend" response.

If I love you more, I will be more likely to hate anyone who hurts you. Makes sense.

Still, it's unlikely that the military will have soldiers whiffing oxytocin any time soon. I think amphetamines are working just fine for them.